Timer 555 Calculator Pro vs SPICE Viewer
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Timer 555 Calculator Pro
Calculate parameters for monostable and astable circuits. Find component combinations for desired pulse width or frequency. Share circuit files via iCloud Drive or AirDrop.
- Calculate monostable pulse width
- Calculate astable frequency
- Find component combinations
- Adjust component tolerance
- Unlimited combinations (Pro)
- Share circuit files
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This app is used to calculate monostable and astable circuit. Features * Calculate pulse width of monostable circuit * Calculate frequency of astable circuit * Find out combination of components making a desire pulse width in monostable circuit * Find out combination of components making a desire frequency in astable circuit * Share file to iCloud Drive (For iOS8 or later) * Share file via AirDrop Additional Features in the Professional Edition * Unlimited number of combinations * Allow to change tolerance * No ads
SPICE Viewer
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SPICE Viewer provides a hierarchical view of SPICE documents, making it easy to navigate complex circuit definitions. It organizes content into structured levels including: Library definitions, Model declarations, Circuit elements, Associated parameters. With a clear tree-based structure, users can quickly inspect relationships between libraries, models, and elements without manually parsing raw SPICE text. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Screenshots
Verdict
The clearest difference is price: SPICE Viewer at Free against Timer 555 Calculator Pro's $0.99. Timer 555 Calculator Pro's advantage is in-app purchases (none vs 4) and iOS requirement (13.2 vs 18.2). On update cadence, ads and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
SPICE Viewer is free to download; Timer 555 Calculator Pro costs $0.99 up front. SPICE Viewer sells 4 in-app purchases, starting at $0.99 per month. Timer 555 Calculator Pro asks for nothing beyond the download.
Timer 555 Calculator Pro ships an update every 3 months, SPICE Viewer every 2 months. The most recent releases landed on October 23, 2026 and October 13, 2026 respectively.
| Parameter | Timer 555 Calculator Pro | SPICE Viewer |
|---|---|---|
| Price | $0.99 | Free — better |
| Rating | 4.7 (3 ratings) — better | — |
| Positive reviews | 100.0% of reviews | — |
| Number of ratings | 3 — better | — |
| Update frequency | Every 3 months | Every 2 months — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Paid | — |
| Devices | iPhone, iPad, iPod — better | iPhone, iPad |
| Requires iOS | 13.2 — better | 18.2 |
| Further details — not scored | ||
| Size | 3 MB | 17 MB |
| Age rating | 4+ | 4+ |
| Developer | Siu Yuen Ho | AIP Technology Corporation, Taiwan Branch |
In-app purchases
Timer 555 Calculator Pro
No in-app purchases
SPICE Viewer
- Viewer(Monthly)3 Days trial$0.991 Month
- Editor(Monthly)3 Days trial$9.991 Month
- Viewer(Annual)3 Days trial$9.991 Year
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- Editor(Annual)3 Days trial$99.991 Year
Questions
Is Timer 555 Calculator Pro free?
Is SPICE Viewer free?
Do Timer 555 Calculator Pro or SPICE Viewer have ads?
Which is updated more often, Timer 555 Calculator Pro or SPICE Viewer?
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